What Is Carotid Ultrasound?

Carotid (ka-ROT-id) ultrasound is a painless and harmless test that uses high-frequency sound waves to create images of the insides of the two large arteries in your neck. These arteries, called carotid arteries, supply your brain with blood. You have one carotid artery on each side of your neck.

Carotid ultrasound shows whether a material called plaque (plak) has narrowed your carotid arteries. Plaque is made up of fat, cholesterol, calcium, and other substances found in the blood. It builds up on the insides of your arteries as you age.

Too much plaque in a carotid artery can cause a stroke. The plaque can slow down or block the flow of blood through the artery, allowing a blood clot to form. A piece of the blood clot can break off and get stuck in the artery, blocking blood flow to the brain. This is what causes a stroke.

A standard carotid ultrasound shows the structure of your carotid artery. Your carotid ultrasound test may include a Doppler ultrasound. Doppler ultrasound is a special ultrasound that shows the movement of blood through your blood vessels. Your doctor often will need results from both types of ultrasound to fully assess if there is a problem with blood flow through your carotid arteries.